By my calculations this would be the max damage on a Deadric Greatsword:
Base damage = 24
Legendary Smithing = +10 damage = 34
100% two hand skill = +40% damage = 48
All Barbarian perks = +100% damage = 95
If I also have 4 pieces of Armour with +25% two hand boast each that gives +100% damage = 190 damage
I understand that power attacks double and sneak attacks make it 15x as big, but people seem to be implying you can get to 600+ damage without these?
What am I missing?